Are One Of The Symptoms Of Low Blood Sugar Mean Streaks?

I don't think so.
However, a person with low blood sugar will become confused and may not realize what he/she is doing and therefore could be mean to someone they aren't normally mean to.
They can become combative as well

The answer is YES, people do become "testy" when the blood sugar drops.  I know this to be a fact because I have that problem.  When the blood sugar drops and I need food, get me food fast! Peanut butter or peanut butter crackers are a good quick fix if food is not immediately available.   It can also cause fainting and heart palpitations and well as a feeling of your insides shaking (I don't know of a better way to describe it).  Your hands can begin to tremble also.  Avoid candy or sugary drinks.  My doctor explained it to me this way:  It is like a roller coaster ride.  When the blood sugar drops it is at the bottom of the ride.  When you try to fix it with candy the blood sugar whips to the top of the ride and you feel fine for awhile but when the sugar drops again it goes even lower than in the beginning.  Never skip meals and eat carbs and protein at each meal.  Exercise can cause a drop in the blood sugar also so be aware of that.  I have had the problem for about 30 + years now and have learned to control it pretty well via diet.  You will soon learn the symptoms and what works best in your case.  Good Luck - this is something that you can handle with a proper diet.  It is not earth shattering, take heart.